A certain metal salt solution is electrolysed in series with a silver coulometer. The weights of silver and the metal deposited are 0.5094 g and 0.2653 g. Calculate the valency of the metal if its atomic weight is nearly that of silver.
Correct answer: B. 2
- A. 1
- B. 2
- C. 3
- D. 4
Explanation
To find the valency of the metal, we use Faraday's laws of electrolysis, which state that the mass of a substance deposited at an electrode is directly proportional to the equivalent weight of the substance. In the given setup, the electrolytic process occurs in series with a silver coulometer, meaning the same quantity of electricity passes through both solutions.The equivalent weight of silver is equal to its atomic weight divided by its valency (1), while the equivalent weight of the metal is its atomic weight divided by its unknown valency (n). Since the atomic weights of silver and the metal are approximately equal, and considering the masses deposited:Equivalent weight of Silver = 0.5094 gEquivalent weight of Metal = 0.2653 gUsing the formula:(Weight of Metal / Equivalent Weight of Metal) = (Weight of Silver / Equivalent Weight of Silver),we can solve for the valency of the metal, yielding a value of 2. This indicates that option B is correct. Options A, C, and D are incorrect as they do not satisfy the proportional relationship derived from the electrolysis process.
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